Dozens of appointments that Gov. Nathan Deal made to state boards and commissions in his final weeks in office could be nixed after a powerful Republican took a dramatic step to challenge whether he followed the proper legal procedure.

In a letter this week, Lt. Gov. Geoff Duncan asserted the 64 board appointments that Deal made between the end of the special legislative session on Nov. 17 and his last day in office on Jan. 14 were not properly submitted to the state Senate.

The letter, addressed to Gov. Brian Kemp, sets up an unusual showdown between the former governor and Duncan, who is seeking to bolster his ties with Kemp and assert himself as a central figure in a fractious and unsettled statehouse.

It could affect a spate of appointments that Deal made during his final weeks in office, including the renewal of three members of the Board of Regents – one of the most coveted posts in state government - and several other prominent boards.

And it reflects a vastly changed dynamic under the Gold Dome, where Republicans with fewer ties to Deal and the political establishment he cultivated now control the levers of power.

The argument involves a Georgia law that requires the Senate to approve a governor's appointments to boards, commissions and bureaus – a vote that's typically approved with little debate or controversy.

When appointments are made in between legislative sessions, the law mandates that the governor must "submit" to the Senate a list of the names. Deal's office sent that list to Duncan on Jan. 14, the day the lieutenant governor was sworn into office.

In a memo accompanying the letter, Duncan attorney Regina Quick argued that the list wasn’t properly submitted because it was sent to the lieutenant governor before he took the oath of office.

Instead, she wrote, the list should have gone to the secretary of the senate, who is the de facto leader of the chamber before a presiding officer is sworn in.

“Any document delivered and addressed to Lt. Gov. Geoff Duncan prior to your swearing-in on Monday, January 14, 2019 is not a submission to the Senate,” wrote Quick, a former judge and GOP lawmaker.

“Any gubernatorial appointments made thereafter would be made by Governor Brian P. Kemp and directed to you as president of the Senate.”

Kemp seems unlikely to oppose the effort, which will yield him additional appointments he can dispense to allies. His office said Thursday it would soon submit its list, but declined to say whether it would include Deal’s appointments.

It’s not immediately clear whether Deal, who is recovering from back surgery, or any of his allies will contest Duncan’s position. A former aide said the office followed proper procedure and notified the Senate of the moves.